Oscar,
How would this work with reflections ? If the camera is animated through a scene that has reflections, how will the reflections up date ?
Or will it be for first and secondary bounces and the reflections will have to render for each frame ?
Also, could baked informantion be used to speed up later frames in some way (I believe they call this illuminance chaching)? In other words, could baking be used to speed up the rendering of moving objects in animations?